Sewing machine



J. KIEWICZ.

SEWING MACHINE.

APPLICATION FILED mm. 23. n20.

1,406,742. Patented Feb. 14, 1922.

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J. KIEWICZ.

SEWING MACHINE.

APPLICATION FILED MAR} 23. I920.

1,406,742. Patented Feb.14; 1922'.

3 SHEETSSHEET 2.

J. KIEWICZ.

SEWING MACHINE.

APPLlCATiON FILED MAR. 23v i920.

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UNITED STATES PATENT OFFICE.

JOHN KIEWICZ, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE REECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

SEWING MACHINE.

' Specification of Letters Patent.

Patented Feb. 14, 1922.

Application filed March 23, 1920. Serial No. 368,205.

Machines, of which the following description, in connection with the accompanylng drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to two-thread sewing machines of the type which are con structed to sew a short seam and then come to rest, and particularly to sewing machines of this type which are equipped with threadtrimming mechanism for cutting the under thread beneath the work at the end of each sewing operation.

The principal object of my invention is to provide an improved device for pulling off a length of under thread at the end of each sewing operation sufiicient to provide for forming the first stitch on the next succeeding operation and for holding the under thread after it is cut.

In my improved device, the thread-holding element is associated with and co-operates with the pull-off device, the arrangement being such that when the pull-off operates to pull off the under thread, it carries the thread into position tobe clamped by a hold-. ing element which co-operates with the pulloif for holding the end after the thread is severed.

in order to give an understanding of my invention, 1 have illustrated it as it might be applied to a buttonhole sewing machine of the Reece type, exem lifications of which are found in United tates Patents No. 1,188,942, June 27, 1916; No. 1,188,944, June 27, 1916; 1,338,373, April 27, 1920, and 1,361,871, December 14, 1920, and inasmuch as the invention relates to the mechanism for pulling off a length of under thread, trimming it. and holding the trimmed end, I have contented myself with showing only those portions of the sewing machine with which my invention co-operates.

lln the drawings, Fig. 1 is a side View of a portion of the buttonhole sewing machine having my improvements applied thereto Fig. 2 is a front view of Fig. 1 with the overhanging arm omitted;

Fig. 3 is an underside View of the bed frame;

Fig. 4 'is a plan view of the clamp plate and a portion of the bed frame showing my improvement Fig. 5 is a detail view similar to Fig. 4, but having the clamp plate and thread-cutting device removed to better show the pulloff and thread-holding member;

b Fig. 6 is an end view of the pull-off mem- Fig. 7 shows the manner in which the thread is clamped after itis cut.

1 indicates a portion of the bed frame of a buttonhole sewing machine from which rises the overhanging arm 2 in which reciprocates the usual needle bar 3 carrying the upper needle 4 by which the upper thread 5 is manipulated. The under thread 6 is manipulated by an under-thread-handling mechanism situated beneath the bed frame 1 and mounted on a turret 7 which is rotatably mountedin bearings carried by the depending portion 8 of the sewing machine frame. This turret is constructed to be rotated when sewing around the ends of the buttonhole, as usual in sewing machines of this type, and it is provided with a hollow spindle 9 through which the under thread 6 is led to the under needle which co-operates with the upper needle 4 to concatenate the upper and under threads. This under needle is usually a curved needle having an oscillatory movement and is-indicated at 10 in Fig. 7.

A suitable tension is provided for the under thread and it is common practice to place this tension on the turret. .1 have indicated in Fig. 2 such a tension at 70, and the under thread 6 is led through a slot 71 in the spindle 9 to a guide-eye 72, and from the latter to the tension 70, said thread extending from the tension to the under needle 10. In Fig 2, the turret is shown in a position to bring the tension 70 on the front side thereof which will be the position during a part of the sewing operation. At the end of the stitching operation, however, and at the time when the pull-off, hereinafter described, is operating, the turret will be in a position 180 from that shown in Fig. 2 with the tension on the back side thereof.

The turret 7 is provided at its upper end with the usual throat-plate 11 having the opening 12 through which the needles 4 and 10 operate and through which the under thread is led to the work. Some sewing machines of this type are provided with means to deliver a stay-cord 13 through the opening 12 of the throat-plate, which stay-cord is laid along the edge of the buttonhole as the latter is stitched.

The work in which the buttonhole is formed is supported on a clamp plate 14 that is slidably mounted in suitable ways 15 formed in the bed frame 1, and said work is clamped by the usual work clamps 16 which are pivotally mounted on the clamp plate. The clamp plate is given a feeding movement in the ways 15 by the main feed cam 17 The parts above referred to are or may be all as usually found in buttonhole sewing machines of this type and constitute no part of my present invention.

It has heretofore been proposed to providev sewing machines of this type with means operating beneath the work to cut the under thread at the end of the stitching operation, and it has also been proposed to provide sewing machines of this nature with means for pulling off a length of under thread from the supply prior to the trimming thereof thereby to furnish a sufiicient length of under thread to ensure the formation of the first stitch at the beginning of the next stitching operation. Devices for this purpose are illustrated in above-mentioned Patents 1,338,373 and 1,361,871.

In my present invention, I provide not only means for trimming the under thread beneath the work at the end of each stitching operation, but I also provide a novel pull-off for pulling off a length of the under thread from the source of supply before the thread is trimmed, and a thread-clamping member which co-operates with the pull-off to clam the severed end of the under thread untila ter the first stitches are formed at the commencement of the next stitching operation. I

The pull-off device is in the form of a pullofl lever 18 which is situated beneath the clamp plate-14; and is pivoted to the bed frame at 19, one end 20 of said lever projecting beyond the front end of the bed frame. The inner end of this lever is pointed, as indicated at 21, and is provided with the notch 22 which forms the hook portion 23. This inner end of the pull-ofi' lever is situated directly beneath and adjacent the throat-plate 11, and when the pull-off lever is in its normal position, the pointed end 21 thereof is directly beneath one side of the throat-plate and in proximity to the open ing 12 therein. The pull-off lever is capable of swinging about its pivot 19 from the full to the dotted line position, Fig. 5, and during this swinging movement, the notched end is carried beneath the throat-plate into the dotted line position and between the stay-cord 13 and the portion of the under thread 6 which extends from the throatplate to the under needle 10. The swinging movement of the pull-ofi' is suflicient to carry the hook 22 beyond the under thread, and during this movement said portion of the under thread wipes by the hook 22 and drops into the notch 23 so that upon the return movement of. the pull-off lever18 into its full line position a bight or bend will be formed in the under thread, as shown at 27, Fig. 7, said under thread passing from the throat-plate 11, around the hook 22, and then back to the needle 10.

As stated above, the pointed end 21 of the pull-off lever is carried between the staycord 13 and the under thread when it is swung into the dotted line position, Fig. 5, and, therefore, said pull-off lever has no effect upon the stay-cord, but acts only on the under thread. The forming of the b ight 27 in the under thread operates to draw a length of under thread through the tension and through the needle 10, the amount of under thread which is thus pulled off being sufficient to provide for the proper formation of the first stitch of the next stitching operation.

Means are provided for actuating the pull-ofi' device at the end of each stitching operation .and before the thread is cut so that the under thread is connected to the work when the pull-ofi' device is moved forward into its dotted line position to engage the under thread and then isretracted to the full line position again. formation of the bend or bight 27 in the under thread by the return movement of the pull-off will operate to draw thread from the source of supply, thus pulling off from the source a sufiicient length of thread to form the first stitch at the beginning of the next stitching operation.

The turret 7 is usually provided with a tension device 70 to produce proper tension in the under thread, and this pulling off of the under thread draws the thread through the said tension device.

The pulling-off lever is acted upon by a pulling spring 31 which normally holds it in its retracted position.

For actuating the pull-off at the proper time, I have provided an actuating lever 28 which is pivoted to the underside of the bed frame at 29, and the'outer end 30 of which is adapted to engage the end 20 of the pullofi lever. This actuating lever is operated by a cam member 32 which is rigid with the main cam 17, for which purpose said cam member is formed with an arm 33 having a roll 34 thereon which is adaptedto engage the inner end 35 ofthe lever 28 at the proper time during the rotation of the cam 17. It

As a result, the

will be understood upon reference to the above-mentioned patents that the cam 17 makes one rotation for each stitching operation, and that in sewing any buttonhole, the stitch-forming mechanism will be brought to rest when the stitching on the buttonhole is completed, and thereafter the cam 17 will continue rotating until the work-holding means has moved to carry the work from stitching to buttonhole-cutting position, at which time the machine as a whole comes to rest. The cam 32 will make one complete rotation for each stitching operation, and the arm 33 is so situated on the cam member 32 that it comes into operation to actuate the lever 28 just after the stitching operation has been completed on any buttonholeand the stitch-forming mechanism has come .to rest, but before the work has been shifted from stitching to buttonhole-cutting position. Therefore, at the end of each stitching operation and before the machine comes to rest, the pull-off lever is actuated to pull off the length of under thread.

During the initial swinging movement of the lever 28 the end 30 thereof engages the end of the pull-off lever 18, and when said lever has been swung into the dotted line position, Fig. 3, then the end 30 wipes by the point 36 of said pullsofi' lever, as shown in dotted lines a, Fig. 5. The movement which is given to the lever 28 is sufficient to carry it into the dotted line position b, Fig. 5, and when it is in thisposition, the spring 31 operates to return the pull-off to the full line position, this being permitted by the concaved or re-entrant portion 37 formed in the inner edge of said pull-ofi' lever.

It will be observed that the pull-off oper-- ates beneath "the throat plate and acts on the portion of the thread between the latter and the needle 10. After the length of under thread has thus been pulled off, said under thread is severed between the throat-plate and the work by means of a suitable cutter herein shown as a cutter element 38 pivoted to the clamp plate at 39 and provided with a shearing edge 40 which is situated to swing over the throat-plate as the cutter swings about its pivot 39. This cutter element is normally held in the full line position Fig. 4 against a stop 41 by means" of a pulling spring 42, and when in this position the shearing edge 40 is situated at one side of the throat plate 11, but directly above the latter.

The clamp plate 14 is provided'with a shear-block 43 on the opposite side of the throat-plate and provided with a shearing edge 44. The cutting member 38 is adapted to swing about its pivot 39 to carry its shearing edge 40 across the shearing edge 44 of the shear-block, and during this swinging movement, the swinging edge engages the under thread 6 directly above the throat plate and between the latter and the work and carries said thread against the shear-.

block thereby severing it.

I propose to actuate the cutting element 38 by means of the actuating lever 28, and I have provided a construction wherein during the initial movement of said actuating lever, it will actuate the pulling-off member to pull off a length of under thread and then to release it, and during the final movement of said lever it will actuate the cutting element 38.

The cutting element is formed on the under side of its outer end 45 with two separated walls 46, and the actuating lever 28 is formed with an upwardly-directed stud or projection 47 which is received between these walls. When the parts are in their normal position which they occupy during the sewing of the buttonhole, the end 30 of the actuating lever lies against the end of the pull-off lever, andthe projection 47 is adjacent to one wall 46, as shown in Fig. 4. When the'actuating lever is given its swinging movement, it first acts on the pulloff lever, as above described, to actuate the latter, and then to release it, and by the time the pull-off lever has been released, the actuating lever 28 has moved into a position to carry the projection 47 adjacent the opposite wall 46, so that during further movement of the actuating lever said projection engages the wall 46 and gives the cutter member its cutting movement. WVhen the roll 34 wipes by the end 35 of the actuating. lever, the latter will be returned to its normal position by a suitable spring 48.

The pull-off lever 18 is made somewhat resilient and is provided on its under side with the inclined face 49 which is situated so that during the backward movement of the actuating lever, the end 30 thereof will engage this inclined face, as shown in Fig. 6. The resiliency of the pull-off lever allows it to spring upwardly so as to permit the actuating lever to pass from under it, and when the actuating lever has been carried beyond the end of the pull-off lever, the resiliency of the latter will bring it into position to be engaged by said actuating lever upon the next forward movement there of. The backward movement of the actuating lever is limited by a suitable stop 50 carried by the base frame.

My invention contemplates a thread-holding device which co-operates with the pulloff lever for holding the severed end of the under thread until after the first stitches are formed on the next succeeding stitching operation. This thread-holding device is in the form of a resilient clamping arm 51 which is situated directly above and in engagement with the inner end of the pull-off lever. This thread-holding member is shown as carried by the base frame 1, and the end 52 thereof is so positioned that it covers the hook 22o-f the pull-oil lever when the latter is in its normal position against its stop 53. When, therefore, the pull-oil lever has moved forwardly to engage the under thread, as shown in dotted lines Fig. 5, and then swings backwardly into its normal position, a portion of the thread will. be carried between the upper face of the pull-off lever and the under face of the resilient thread-holding member 51, as shown clearly in Fig. 7, and the under thread is, therefore, frictionally clamped between the throat-plate and the needle 10. When, therefore, the under thread has been severed by the cutting element 38, the severed end will be thus held by the co-operation of the pull-off lever and holding member 51 until the stitching begins on the next succeeding operation. When the first stitch is formed, the needle 10 is carried up through the throat-plate, but the end of the under thread will be held beneath the throat-plate and thus the first stitch can be correctly formed. As the stitching continues, the feedin movement of the work will draw the en of the thread from between the holding member and pull-off lever.

have shown the holding member 51 as pivoted to the bed frame at 54. and as held in its operative position against a stop 55 by means of a pulling spring 56. The purpose of makind the holding member pivoted is so as to permit it to be swung back out of the way in case it is necessary to remove the pull-off lever or adjust the latter.

I have also shown the hooked end of the pull-off lever as made on a part 57 which is pivoted to the body of the lever at 58, and which is provided with a finger 59 adapted to engage one edge of the main portion of the lever and to which the pulling spring 31 is fastened. The object of making the active end of this pull-01f lever in a separate part pivoted to the main portion is so that.

if the turret should not be in proper position when the pull-ofi' lever is actuated, the engagement of the operative endthereof with the turret would simply swing the part 57' backwardly without injuring any part. The spring 31 thus serves not only to yieldingly hold the part 57 in its operative position, but also acts as a return spring for the pulloff lever 18.

It will be remembered that the pull-off lever 18 operates to pull off a length of under thread from the source of supply through the tension 70 on the turret 7. It sometimes happens that the under thread becomes tanwhich operates between the tension 7 0 on the turret and the source of supply for drawing a length from the source of supply before the pull-ofl lever 18 operates to pull this length through the tension on the turret. The pulling ofthe thread from the source of supply is thus accomplished-in two stages. This auxiliary pull-off is in the formof a lever 60 which is fast on a rock-shaft 61 carried by the frame, and the outer end of which is provided with an eye 62 through which the under thread 6 extends. The end of the lever operates between two guide arms 63, 64, each of which has an eye for the under thread 6, said arms being carried by a suitable bracket 67 secured to the frame. The guide-eye 62 is normally in line with the guide-eyes in the arms 63, 64:, but means are provided for actuating the rock-shaft 61 and thereby swinging the lever 60 in a vertical direction just before the pull-off lever 18 is actuated. Such movement of the lever 60 will pull off a length of underthread from the source of supply, so that when the pulloff lever 28 operates, it will simply draw through the tension on the turret the slack thread which has been drawn'from the source of supply by the lever '60. Any suitable means for actuating the'rock-shaft 61 may be provided. I have herein chosen to employ for the rock-shaft '61 the rock shaft which actuates the pull-oil for the upper thread shown in my patent No. 1,188,944.. buch rock shaft has an arm 62' rigid therewith provided with afroll 63 which is actuated by 1 a cam portion 64- on the cam 32. This cam portion 64 is so situated relative to the arm 33 that it will actuate the rock shaft 61 just before the arm 33 actuates the lever 28 and, therefore, with this timing of the parts, the 106 auxiliary pull-,ofi' arm 60 will operate to pull off a length of under thread from the source of supply just before the pull-off arm 28 is actuated to pull the length of under thread through the tension on the turret.

I claim: V

1. In a two-thread sewing machine adapted to sew a short seam and then come to rest, the combination with stitch-forming mechanism' including means to manipulate the un- 18 der thread, of a throat plate beneath the work, means operative automatically at the end of the sewing operation to pull off a length of under thread from the source of supply, means operated automatically to cut said under thread between the work and the throat plate, and means co-operating with the pull-ofl to hold the severed end.

2. In a two-thread sewing machine adapted to sew a short seam and then come to rest, 12$ the combination with mechanism for handling the under thread, of a throat-plate beneath the work, means operative automatically at the end of the sewing operation to act on t-he under thread between the throatplate and the source of supply and pull off a length of under thread, automatically actuated means to out said under thread between the Work and the throat plate, and means co-operating with the pulling-01f device to clamp the severed end.

3. In a two-thread sewing machine adapted to sew a short seam and then come to rest, the combination with mechanism for handling the under thread, of a throat-plate beneath the work, means operative automatically at the end of the sewing operation to act on the under thread between the-throat plate and the source of supply and pull oif a length of under thread, automatically actuated means to cut the under thread above the throat-plate, and means co-operating with thel pulling-ofi device to clamp the severed en 4:. In a two-thread sewing machine, the combination with a bed frame, of work-holding means movab-ly mounted thereon, a turret rotatably mounted beneath the bed frame and provided with a throat plate underthread-handling mechanism carried by the turret, a pull-oil device adapted to engage the under thread beneath the throat-plate and draw ofi a length from the source of supply, means to actuate said device at the end of the sewing operation, means to cut the under thread above the throat-plate after said length has been pulled off, and means co-operating with the pull-off device to clamp the severed end of the thread.

5. In a buttonhole sewing machine, the combination with abed frame, of workholding means mounted thereon, a turret situated beneath the bed frame and provided with a throat-plate, a pull-ofi' device adapted to engage the under thread beneath the throat-plate and draw off a length from the source of supply, a cutter operating above the throat-plate to cut the under thread, an actuator common to both the pull-off device and the cutter, and means co-operating with the pull-01f device to hold the severed end of the thread.

6. In a buttonhole sewing machine, the combination with a bed frame, of workholding means mounted thereon, a turret situated beneath the bed frame and provided with a throat-plate, a pull-ofi' device adapted to engage the under thread beneath the throat-plate and draw off a length from the source of supply, a cutter operating above the throat-plate to cut the under thread, an actuator common to both the pulloff device and the cutter and arranged to actuate first the pull-elf device and then the cutter, and means co-operating with the pull-ofi device to hold the severed end of the thread.

7. In a two-thread sewing machine, the combination with a bed frame, of workholding means movably mounted thereon, means for manipulating the under thread, a pull-off lever pivoted to the bed frame and provided with a hooked end to engage the under thread and pull off a length from the source of supply, a resilient clamping member situated so that as the thread is pulled off by the pull-off lever said thread is carried between the lever and clamping member and thereby clamped, means to cut the thread between the pull-off and the work and means for actuating automatically said pull-off lever and cutter in timed relation with the other movements of the machine.

8. In a buttonhole sewing machine constructed to lay a stay-cord at the edge of the buttonhole and to form the buttonhole stitches over said stay-cord, the combination with a throat-plate having an opening for the passage of the stay-cord and the under thread, of a pivoted pull-ofi' lever having a pointed end arranged so that when the lever is swung forwardly said pointed end will enter between the stay-cord and the under thread, said pull-oil lever having a hook to engage the under thread whereby during backward movement of the lever a length of under thread is drawn from the source of supply, and means to cut the under thread close to the work.

9. In a buttonhole sewing machine constructed to lay a stay-cord at the edge of the buttonhole and to form the buttonhole stitches over said stay-cord, the combination with a throat-plate having. an opening for the passage of the stay-cord and the under thread, of a pivoted pull-off lever having a pointed end arranged so that when the lever.

is swung forwardly said pointed end will enter between the stay-cord and the under thread, said pull-off lever having a hook to engage the under thread, whereby during backward movement of the lever a length of under thread is drawn from the source of supply, means to out the under thread close to the work, and means co-operating wigh the pull-off lever to hold the severed en I 10. In a two-thread sewing machine adapted to sew a short seam and then come to rest, the combination with stitch-forming mechanism, of a tension device for the under thread, means normally inoperative during the operation of the stitch-forming mechanism but which become operative at the end of the sewing operation toact on the under thread between the tension and the source of supply and to draw off a length of under thread, and other means operative subsequently to the first-named means to draw said length of under thread through the a tension.

11. In a two-thread sewin machine adapted to sew a short seam and then come to rest, the combination with a stitch-forming mechanism, of a tension device for the under thread, means operative after the stitch-forming mechanism comes to rest to 5 pull off a length of under thread between the work and the tension device, and an auxiliary pull off acting on the thread between the tension device and. the source of supply.

In testimony whereof, I have signed my name to -this specification.

JOHN KIEWIOZ. 

